"Happy Birthday Mom! Your unconditional love has made me who I am today. You are my rock. My (heart). I'll always be your Miche. I love you," the former first lady wrote to her mother, Marian Robinson.

Obama has shared the impact her mother has had on her life and the lives of her daughters in the past. Robinson lived with the Obama family at the White House for much of her son-in-law's presidency.